Processing Forum
void setup() {
size(400, 400);
stroke(255, 0, 0);
noFill();
smooth();
}
void draw() {
background(0);
if (mousePressed==true) {
if (a > 200) {
a = 0;
}
ellipse(200,200,a,200);
ellipse(200,200,a,100);
ellipse(200,200,a,50);
tint(255, 0);
a++;
if (b > 200){
b=0;
}
ellipse(200,200,200,b);
ellipse(200,200,100,b);
ellipse(200,200,50,b);
b++;
}